Electric condenser



March 14, 1944. J. L. FINQH ELECTRIC oonmmsmz INVENTOR Filed Dec.-2l, 1940 Jama-t'lfiick BY M ATTORNEY Patented Mar. 14, 1944 2,344,239 ELECTRIC CONDENSER James L. Finch, East Rockaway, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application December 21, 1940, Serial No. 371,073

6 Claims.

the inside wall of the casing more tightly upon an increase of pressure.

A feature of this invention is the novel arrangement of an insulator which is placed within the casing in such a manner that a shouldered end portion of the insulator compresses gasket material which bears against the inside wall of the casing.

Another feature of this invention is the novel method of centering th insulator axis with respect to the axis of the condenser casing.

Condensers of the fluid type are known in the prior art. The condenser insulator, however, is most usually placed outside of the casing and has a flange which is arranged to extend beneath a clamp ring and a gasket member which is secured to the outside of the casing by any suitable means in order to seal the joint between the insulator and easing. In such a construction, however, there is a tendency for the pressure within the casing to expand the clamp ring and gasket and thus give rise to undesirable leakage of the fluid pressure. The improved construction of my invention prevents fluid pressure leakage by placing the insulator flange portion within the casing and placing a gasket between the insulator and the inside wall of the casing so that an increase v of fluid pressure seals the casing more tightly.

Condensers of my invention are primarly directed to condensers of the compressed air type,

such as disclosed in the Hansell et al. Patent -#2,192,062, issued Feb. 27, 1940, and although for This invention will best be understood by referring to the accompanying drawing, in which:

Fig. 1 is a longitudinal section of the condenser of my invention; and

Fig. 2 is a bottom view of Fig. 1.

Referring now in detail to the drawing, the condenser casing -i is made preferably from extra heavy brass pipe having its upper end Ia shaped over to form an inwardly extending shoulder portion by hammering over a steel form. The inner portion of the upper end is accurately turned to fit a tapered shouldered portion on insulator 2. The bottom portion of the casing is threaded at lb to receive a flange base ring 3. An internal threaded portion I0, is threaded to receive an insulator adjusting ring 4. The inner surface of easing 1 between portions l0 and lb is accurately ground and polished to prevent brushing to adjacent electrodes and thus forms one of the electrode surfaces of the condenser. The insulator 2 is assembled within the casing so that its tapered shoulder portion 2a bears against the tapered portion Id of the casing. The tapered portions Ia and 2a are coated with a heavy paste of Fostoria Tight Seal. A lead gasket 5 is provided to prevent leakage of the internal fluid, also, entry of air and moisture from the outside atmosphere. The axis of insulator 2 must be accurately maintained at the same axis of the casing for thereason that condensers of this type are employed in circuits having relatively high voltages. Therefore, it is absolutely necessary that the electrodes be maintained in exact concentric relationship, and in order to maintain the insulator in this exact relationship, there is provided a bearing clamp ring 6 which is placed beneath the flange portion of insulator 2 and is arranged to be clamped between adjusting ring 4 by means of eight safety hollow set screws 1 having a cup point. Set screws I also serve to clamp insulator 2 against the inside wall of the casing by applying pressure thereto. To further prevent air leakage and also damage to the insulator, a 'second lead gasket 8 is interposedbetween insulator 2 and bearing ring 6. The lower end of the casing is provided with a base plate 9 and is retained in a fluid-tight manner by means of a plurality of set screwslll. A suitable gasket H is interposed between base ring 3 and casing l. The insulator 2 has a relatively long narrow cone-shaped inner surface which provides a large electrical creepage surface as condensers of this type are particularly desirable for use in ultrahigh frequency circuits and with such an arrangement the condenser is capable of withstanding 30,000 peak volts for a relatively long period. A second electrode surface I2 is threaded to the inside portion of base plate 9. The upper portion oi inner electrode I2 is closed by means of a cover plate I3 which is soldered at a point I4. A relatively small aperture I5 in cover I3 gives an improved safety factor to the condenser by reducing the explosion eflects due to rapid expansion of the fluid within the casing when any part of the condenser structure fails. The space within members I2 and I3 serves as a storage tank, also, the space within member I2 encloses suitable filtering means lb to filter out moisture and dust and thus greatly improves the voltage rating of the condenser and extends its useful life. A more complete and detailed description of this arrangement will be found disclosed in the Usselman Patent. #2,210,050, issued Aug. 6, 1940. A third electrode surface I6 is supported by being soldered to a disc member Il, the latter being secured to a shaft or terminal electrode I8 by means of three flat-head screws I9 which pass through a recessed portion I la in member H. The upper portion of shaft I8 seats against a shouldered portion 20 on insulator 2. A lead gasket 2| is interposed between the shouldered portion 20 and the insulator 2. A brass collar or terminal washer 22 is threaded on the extreme upper end of shaft IB and is retained in place by a clamp nut 23, leakage of the fluid within the condenser being prevented by means of a relatively heavy lead gasket 24 which is interposed between the top of insulator 2 and the underside of terminal washer 22. For making electrical connection to the central electrode terminal of the condenser, a plurality of threaded apertures 25 are provided. Casingl is equipped with an air valve 26 and cap 21, valve 26 being soldered to casing I at a threaded portion 28 to prevent leakage of air within the casing. In order that the dielectric fluid within the casing which may be air, gas or compressed liquid under pressure may be accurately determined, a pressure gauge 30 is provided having a scale with indications from zero to three hundred pounds pressure.

Although only one modification of this invention is disclosed, it is to be distinctly understood that it should not be limited precisely thereto.

What is claimed is:

1. an electric condenser capable of operating at an internal fluid pressure different from atmospheric pressure, said condenser including an approximately cylindrical casing, means near one end of said casing forming an inwardly extending annular shoulder faced toward the higher pressure and held against movement axially of said casing in a direction toward the lower pressure, said inwardly? extending shoulder being formed by an inwardly bent marginal end portion of said casing itseli, a dielectric closure member extending across said casing near said end and seated substantially against the side or said shoulder which is toward the higher pressure, so

" that an increase in the fluid pressure diflerence within and without said casing will tend to seat said dielectric member more flrmly against said shoulder, means closing the opposite end of said casing in a substantially fluid tight manner, a first metallic electrode mounted within said casing, and a second metallic electrode spaced from the flrst electrode and supported from said dielectric member.

2. An electric condenser capable of operating at an internal fluid pressure diflerent from atmospheric pressure, said condenser including a casing, a first metallic electrode mounted concentric within said casing, said casing having an inwardly extending shoulder portion formed by the casing itself, an insulator having a tapered shoulder portion of substantially the same contour as the inwardly extending shoulder portion of said casing, said tapered shoulder portion of said insulator seated substantially against the side of said inwardly extending shoulder which is toward the higher pressure, so that an increase in the fluid pressure difierence within and without said casing will tend to seat said insulator more firmly against said inwardly extending shoulder, a shaft supported from said insulator and extending within said casing, and a second metallic electrode mounted on said shaft within said casing and concentrically spaced from said first electrode, and means within said casing for applying pressure to retain said insulator in a central location within said casing to give sealing protection against ingress or egress oi fluid pressure between said insulator and said casing. 3. An electric condenser capable of operating at an internal fluid pressure higher than the outside atmospheric pressure, said condenser including a casing, a flrst metallic electrode-mounted within said casing, said casing having an inwardly extending shoulder portion formed by the easing itself, a threaded portion within said casing, a dielectric element forming a closure seated substantially against the side of the inwardly extending shoulder portion of said casing which is toward the higher pressure and making a tight sealing joint therewith so that an increase in fluid pressure difference within and without said casing will tend to seat said dielectric element more firmly against said shoulder, a threadedadjusting ring secured to the threaded portion oi! said casing, means on said ring to clamp said dielectric element within said casing, a shaft supported from said dielectric element and extending within said casing and a second metallic electrode mounted on said shaft within said casing and spaced from said first electrode.

4. An electric condenser capable of operating at an internal fluid pressure higher than the outside atmospheric fiuid pressure, said condenser including a casing, a first metallic electrode mounted within said casing, said casing having an inwardly extending shoulder portion formed by the casing itself, a threaded portion within said casing, a dielectric element forming a closure seated substantially against the side of the inwardly extending shoulder portion of said casing which is toward the higher pressure and making a tight sealing joint therewith so that an increase in fluid pressure difference within and without said casing will tend to seat said dielectric element more firmly against said shoulder, a threaded adjusting ring secured to the threaded portion of said casing, a clamp ring located intermediate said dielectric element and said 'threaded adjusting ring, means in said threaded adjusting ring to apply pressure to said clamp ring to clamp said dielectric element within said casing, a shaft supported from said dielectric element and extending within said casing and a second metallic electrode mounted on said shaft within said casing and spaced from said first electrode.

5. An electric condenser capable of operating at an internal fluid pressure higher than the outside atmospheric fluid pressure, said condenser including a casing, a first metallic electrode mounted within said casing, said casing having an inwardly extending shoulder portion formed by the casing itself, a threaded portion within said casing, a dielectric element forming a closure seated substantially against the side of the inwardly extending shoulder portionof said casing which is toward the higher pressure and making a tight sealing joint therewith so that an increase in fluid pressure difference within and without said casing will tend to seat said dielectric element more firmly against said .shoulder, an adjusting ring having a threaded flanged portion secured to the threaded portion of said casing, means passing through said ring to clamp said dielectric element in said casing, a shaft supported from said dielectric element and extending within said casing, and a second metallic electrode mounted on said shaft within said casing and spaced from said first electrode.

6. An electric condenser capable of operating at an internal fluid pressure higher than the outside atmospheric fluid pressure, said condenser including a casing having an inwardly extending shoulder portion formed by the casing itself, a threaded portion within said casing, a first metallic electrode mounted within said casing, a dielectric element forming a closure seated substantially against the side of the inwardly extending shoulder portion of said casing which is toward the higher pressureand making a tight sealing joint therewith so that an increase in fluid pressure diiference within and without said casing will tend to seat said dielectric element more firmly against said shoulder, a threaded adjusting ring secured to said threaded portion within said casing, means including screws passing through threaded apertures in said ring to clamp said dielectric element within said casing, a shaft supported from said dielectric element and extending within said wing, and a second electrode mounted on said shaft within said casing and spaced from said first electrode.

JAMES Ll FINCH. 

